This project constitutes one of the two major laboratory research focuses of this section. The goals are to identify, map and characterize varicellazoster virus genes and proteins, expressed during active, latent, or productive infections, and to define the temporal sequence and control of gene expression. To accomplish these ends we use an extensive array of molecular biological techniques. To date we have mapped the viral genome and most of its transcripts. We have identified and carefully mapped a number of important viral gene products. We defined the molecular basis for drug resistance to acyclovir in laboratory derived and human VZV strains. Recently, we proved that VZV remains latent in satellite cells of human sensory nerve ganglia and that some, out not all, VZV genes are expressed during latency. Our current effort is most heavily directed at better defining the nature and control of VZV gene expression in latently infected human tissues.